With hot weather on the way for most of the country, it’s time for managers to consider how to protect workers not fortunate enough to spend all day in air-conditioned cabs or shops.
According to OSHA Emergency Preparedness Guidelines, workers can be exposed to heat stress when their deep internal core temperature rises higher than 100.4 F. That’s the point where your organs begin to lose function and, well, slowly cook.
In addition to high air temperatures, culprits for inducing heat stress can include high humidity, radiant heat sources, direct physical contact with hot objects, or strenuous physical activities.
Also, let’s not forget indoor operations employees may be exposed to in the course of their work—places like foundries, dedicated paint and welding shops, electrical utilities (especially boiler rooms), chemical plants, mining sites, smelters, and steam tunnels. Many of those locations already require full-body Personal Protective Equipment (PPE), which have the potential to make people even hotter, and not in a good way.
In construction, we’re used to PPE for visibility or protection from falls or impacts, but there are several types of PPE effective in minimizing heat stress, among them:
o Reflective clothing
o Auxiliary body cooling ice vests
o Wetted clothing
o Water-cooled garments
o Circulating air.
Per the OSHA Technical Manual on Heat Stress, circulating air is the most effective personal cooling system. Vortec, a division of Illinois Tool Works, actually makes air-conditioned vests. That's right: personal air-conditioners (PACs).
Vortec Personal Air Conditioning Vests circulate cool air to minimize temperature-related stress and fatigue, thus improving comfort and productivity, the company says. The PACs use a vortex tube to reduce the temperature of the air circulating through the vests, which diffuses the airflows around the worker’s torso (so vortices do exist outside Sedona).
These vortex tubes produce up to 6,000 BTU/hr (1,757 watts) of refrigeration and temperatures as low as -40 F to “solve a variety of industrial spot cooling and process cooling needs.” They have no moving parts, and require no electrical connection at the cooling site. Vortex tubes rely on compressed air spinning in the tube to separate the air into cold- (and hot-) air streams. Tube models range from 6 to 13 inches long with cooling capacities from 100 to 6,000 BTU/hr. Vortex tube performance is adjustable by changing the inlet air pressure, ratio of cool air to exhaust, or by changing the generator in the tube itself. And though normally used for cooling, vortex tubes can also be used for heating applications by channeling the exhaust hot air to the application.
The circulating air for cooling is up to 60 F cooler than the ambient temperature. The PVC vests are available in three sizes and provide continuous cooled (or warmed) air through their perforated lining. The vests don't restrict movement or absorb sweat or other contaminants, and can be worn under other protective clothing. You'll have a secret no one can see, and this time it’s a positive one!
Finally, if you’re going on “Jeopardy!” any time soon, remember that French physicist Georges Ranque invented vortex tube technology in 1930 (and it was first developed for industrial use by Vortec in the 1960s).
You’ll be ready to confidently say, "I'll take Anti-organ-cooking Technology for 800, Alex."
